HISTORY OF GALVANISM. 9! 



electric condition of the atmosphere, but ceases or 

 proceeds irregularly when any considerable cjiange 

 occurs in this respect. If the action of the instru- 

 ment were galvanic, or essentially connected with 

 any chemical change in the state of its component 

 parts, it is not probable that the atmospheric elec- 

 tricity would have affected it in so great a degree 

 and in so uniform a manner. 



I shall anticipate a little the chronological order 



of discovery by giving an account in this place of P 

 an instrument, supposed to be analogous to De 

 Luc's, which has been constructed by Professor 

 Zamboni, of Verona. Zamboni's pile, as it was 

 first announced, consisted of disks of silvered paper, 

 to the plain side of which was applied a layer of 

 the black oxide of manganese mixed with honey. 

 In this state it could not literally be entitled to 

 the appellation of a dry pile, but it is said that it 

 has been since constructed upon a less exception- 

 able principle. The most curious property of 

 Zamboni's pile is the degree in which it exhibits 

 the electrical attractions and repulsions. If two of 

 these piles be placed at the distance of four or five 

 inches from each other, and a metallic needle be 

 properly suspended between them, it will be alter- 

 nately attracted by the two piles, so to move be- 

 tween them like a pendulum. This action, we 

 may presume, is certainly electrical ; but the pile of 

 Zamboni appears likewise to have a proper chemi- 

 cal action ; for when it has been confined for some 

 time in a limited portion of air, the air becomes 



